I don't think they're high as they seem to add up/subtract on the scale predictably

and I've been a cardio junkie my whole life and if I had to characterize my 'skill' I'd say I'm in pretty solid cardiovascular shape...I *think* my resting heart rate would seem to lend evidence to this, but I dunno how relevant that is

Lyle what are your thoughts on my wanking about the energy stuff...500 calories burned still reduces the surplus I'm shooting for, regardless of benefits right?

its not as if placing cardio on off days only magically ensures training surplus goes into muscle as much as possible and cardio induced reduction of that surplus comes only out of fat?

Lyle, I was hoping you could give some advice on longer stretches of cardio. Specifically, I will be training for and running a couple half marathons. For a long run (say an hour and a half to two hours, performed weekly), what size of catabolic effect am I going to be dealing with? Should I do anything nutritionally (e.g. consume protein during or immediately after) to help offset these effects? Should I reduce/eliminate the long running and just build an aerobic base via shorter runs?

To be clear, I am currently cutting fat and would like to preserve as much muscle as possible (and possibly even make some newbie gains). I will probably switch to a mass-gaining workout in a month or so, so I'm interested in the effect on half-marathon training on muscle mass in both "cutting" and "bulking" states.

I've read your article, it seems that your only recommendations are total time and heart rate, I've been doing some tests in an elliptical machine and for the same HR 135bpm but changing the intensity level of the exercise the results are very different.

I mean for a hight resistance low pace exercise 135bpm Hr I burn 960Kcal/h, for a low intensity hight pace 135bpm Hr I burn 310Kcal/h accordingly with machine estimations. I suppose that the machine is doing some estimations and numbers are not real but a difference of 3 times is too much error to be attributed to estimations errors, it seems that caloric expenditure is not very correlated with HR and nature of exercise or the way of doing the same exercise is very important.

My question is, what is better for a given HR, doing a hight intensity exercise that burns a lot more calories or a low intensity exercise but with more faster movements and more muscle contractions that burns less calories, it seems that the first is more time efficient but in term of muscle catabolism and overtraining who is better? I mean for building/maintaining muscle what is better?

"In terms of intensity, I think keeping things in the low to moderate range is going to be best. More specifically, a maximum intensity of 70% of maximum heart rate (140 beats per minute for someone with a maximum of 200 beats) or even lower should achieve some benefits without cutting into recovery or growth."

What would be the lowest of intensity one could use and still achieve the improved calorie partitioning and keeping the fat burning pathways active mentioned?

Also, how old are you? If you're kinda old, your max heart rate won't be 200.

I'm 35, my max heart rate might be 185, so that puts 70% at 129. i'm also not in particuarly good aerobic shape. I usually go around 120-125 when I'm doing truly low intensity cardio.

I'm 27 and I'd say in pretty good aerobic shape. I've been uphill walking for cardio pretty intensely for the last while (incline 10, 4.0 mph). I think cutting this intensity would be good for my leg recovery, but at the same time I don't want to cut the intensity too much and miss the benefits completely. Flat brisk walking seems almost too easy, but maybe that's all I need....

I'm incorporating cardio on off days because of the recommendations. I like cardio, so it's not a problem; I'd only previously avoided it because I'd figured it would be detrimental to mass gains. But since I don't have trouble consuming wild amounts of food, the benefits would seem to outweigh the drawbacks.

I'm currently lifting three times per week, and doing cardio on 4 off-days. I have also used a schedule with lifting four times per week, in which case I'd do cardio on the three off-days. I really dislike doing cardio after lifting (preferably not even on the same day), so I'd prefer to avoid that.

The cardio is not very intense - fast walking with a moderate incline, or some light-to-moderate elliptical work, for about a half-hour. Heart rate is around 115-130 BPM, I'd estimate my max to be about 200 BPM.

Would it be wise to drop one of those cardio days in the name of getting a full day of rest, or is it okay to be doing something every single day?